Control method and system
AssigneeRockwell Automation Technologies, Inc.
InventorsDavid M. Messersmith, John Herman Blakely
Life of this patent
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Abstract
Systems, methods, and devices are disclosed, including an induction-motor controller that has a motor controller configured to receive alternating current (AC) power with a voltage that varies generally sinusoidally and transmit the AC power during a conduction angle of a cycle of the AC power. In some embodiments, the conduction angle varies generally sinusoidally at a lower frequency than the AC power, and the motor controller may be configured to not transmit the AC power outside of the conduction angle.
Claims20
A device, comprising:
- a controller configured to receive alternating current (AC) power with a phase voltage that varies generally sinusoidally and transmit the AC power during a conduction angle of a cycle of the AC power, wherein the conduction angle varies generally sinusoidally at a lower frequency than the AC power and is controlled by a controllable reference voltage, and wherein the controller is configured not to transmit the AC power outside of the conduction angle.
A method for controlling an electric motor, the method comprising:
- determining a plurality of controllable reference voltages corresponding to a waveform having a waveform frequency based upon a command frequency;
- applying AC incoming power to a plurality of solid-state switches;
- switching the switches in accordance with timing based upon the controllable reference voltages to generate output power at the waveform frequency, wherein the timing corresponds to a conduction angle of the AC incoming power that varies generally sinusoidally at a lower frequency than the AC incoming power;
- and
- applying the output power to a motor.
A method of controlling electrical power, the method comprising:
- applying incoming AC power to a switch, wherein the incoming AC power has a phase voltage that varies generally sinusoidally through an incoming cycle at an incoming frequency;
- providing a generally sinusoidal controllable reference voltage having a reference frequency, wherein the reference frequency is less than the incoming frequency;
- and
- switching the switch during a conduction angle of the incoming cycle, wherein the size of the conduction angle depends on the magnitude of the sinusoidal controllable reference voltage.
Dependencies are inferred from the claim text.